From: Jonathan Paisley <jp-www@...>
Date: 2004-11-24T18:53:05+09:00
Subject: Breakpoint/Drb (was [SOLUTION] Object Browser (#8))

Hi Florian,

Would you consider adding some description (such as your text below) to
the Drb version of breakpoint.rb? I spent some time reading the code to
figure this out, and perhaps it might be a useful addition to help others
to get an overview of how it works.

On a related point, I discovered that if I attempt tab completion in the
Drb-ified IRB session the server side crashes since it uses plain eval()
against a Drb-proxy of the binding, which fails. Any idea how to fix this?

ruby--1.8.2p2/lib/ruby/1.8/irb/completion.rb:160:in `eval': wrong argument type DRb::DRbObject (expected Proc/Binding) (TypeError)

Many thanks.
Jonathan

On Tue, 23 Nov 2004 21:07:25 +0100, Florian Gross wrote:

> The remote ones work by running part of an irb session at the server and 
> part of it on the client. The communication is done transparently via 
> DRb. This required a bit of hacking, but in this case the only important 
> thing is really that you can use drb_service.evaluate(nil, code) for 
> evaluating arbitrary code.
> 
> Breakpoints themself just cause an IRB shell to spawn in the current 
> context at the current line of code. Some Binding.of_caller magic is 
> used for making the interface transparent.
> 
> There's a few extensions over that basic principle (assume, being able 
> to return a custom value from a breakpoint, getting the source code 
> where the breakpoint was triggered and so on), but it's really all not 
> too complex.
> 
> Feel free to ask if that explanation was not in detail enough for your 
> needs. I'd be pleased to help out. I think a good GUI interface like the 
> ones you and Jamis did would really be a very nice addition to the 
> Breakpoint package. (And also dev-utils, IMHO)